package com.dsshare.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.codec.binary.Base64;
/** *//**
     * <p>
     * BASE64编码解码工具包
     * </p>
     * <p>
     * 依赖javabase64-1.3.1.jar
     * </p>
     *
     * @author IceWee
     * @date 2012-5-19
     * @version 1.0
     */
    public class Base64Utils {

        /** *//**
         * 文件读取缓冲区大小
         */
        private static final int CACHE_SIZE = 1024;

        /** *//**
         * <p>
         * BASE64字符串解码为二进制数据
         * </p>
         *
         * @param base64
         * @return
         * @throws Exception
         */
        public static byte[] decode(String base64) throws Exception {
            return Base64.decodeBase64(base64.getBytes());
        }

        /** *//**
         * <p>
         * 二进制数据编码为BASE64字符串
         * </p>
         *
         * @param bytes
         * @return
         * @throws Exception
         */
        public static String encode(byte[] bytes) throws Exception {
            return new String(Base64.encodeBase64(bytes));
        }

        /** *//**
         * <p>
         * 将文件编码为BASE64字符串
         * </p>
         * <p>
         * 大文件慎用，可能会导致内存溢出
         * </p>
         *
         * @param filePath 文件绝对路径
         * @return
         * @throws Exception
         */
        public static String encodeFile(String filePath) throws Exception {
            byte[] bytes = fileToByte(filePath);
            return encode(bytes);
        }

        /** *//**
         * <p>
         * BASE64字符串转回文件
         * </p>
         *
         * @param filePath 文件绝对路径
         * @param base64 编码字符串
         * @throws Exception
         */
        public static void decodeToFile(String filePath, String base64) throws Exception {
            byte[] bytes = decode(base64);
            byteArrayToFile(bytes, filePath);
        }

        /** *//**
         * <p>
         * 文件转换为二进制数组
         * </p>
         *
         * @param filePath 文件路径
         * @return
         * @throws Exception
         */
        public static byte[] fileToByte(String filePath) throws Exception {
            byte[] data = new byte[0];
            File file = new File(filePath);
            if (file.exists()) {
                FileInputStream in = new FileInputStream(file);
                ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
                byte[] cache = new byte[CACHE_SIZE];
                int nRead = 0;
                while ((nRead = in.read(cache)) != -1) {
                    out.write(cache, 0, nRead);
                    out.flush();
                }
                out.close();
                in.close();
                data = out.toByteArray();
            }
            return data;
        }

        /** *//**
         * <p>
         * 二进制数据写文件
         * </p>
         *
         * @param bytes 二进制数据
         * @param filePath 文件生成目录
         */
        public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
            InputStream in = new ByteArrayInputStream(bytes);
            File destFile = new File(filePath);
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            OutputStream out = new FileOutputStream(destFile);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            in.close();
        }


    }
